class Solution {
public:
    bool checkSubarraySum(vector<int>& nums, int k) {
        unordered_map<int,int>m;
        m[0] = -1;
        int sum = 0;

        for(int i = 0;i < nums.size();i++){
            sum += nums[i];
            if(k != 0){
                sum %= k;
            }

            if(m.count(sum) > 0){
                if(i - m[sum] > 1) return true;
            }
            else{
                m[sum] = i;
            }

        }
        return false;
    }
};